Light emitting and image sensing device and apparatus

ABSTRACT

There is provided a light emitting and image sensing device for a scene. The light emitting and image sensing device is formed in a semiconductor substrate and comprises a photoemitter means for illuminating the scene with light, and a photosensor means for sensing an image of the scene. The photosensor means is responsive to incident light from the scene. In another embodiment of the present invention there is provided a light emitting and image sensing device for a scene. The light emitting and image sensing device includes a photosensor means for sensing the image of the scene, the photosensor means is formed in a first semiconductor substrate and is responsive to incident light from the scene, and a photoemitter means for illuminating the scene with light, the photoemitter means is formed in a second semiconductor substrate. The second semiconductor substrate is attached to the first semiconductor substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel image sensor device, hereinreferred to as a light emitting and image sensing device, and theapparatus in which it is used.

2. Description of the Related Art

An embodiment of a conventional image sensor, in this case a CMOS imagesensor, is schematically illustrated in cross-section in FIG. 1. Amicrolens 30 focuses incident light, or photons 32, on a plurality ofphotodiodes 34 in a silicon substrate 36. Color filters 38 filterphotons of specific wavelengths so that each of the photodiodes 34collects photons within one of three ranges of wavelengths,corresponding to red, green and blue light.

An embodiment of a conventional active pixel element in a CMOS imagesensor is illustrated in schematic view in FIG. 2. The active pixelelement comprises a photodiode and an active pixel circuit indicatedgenerally by reference numerals 34.2 and 40 respectively. The photodiode34.2 provides a photosensor signal on conductor 42. The photosensorsignal on conductor 42 is read out through a buffer transistor 44 onto acolumn bus 46 when a row select transistor 48 is activated. A resettransistor 50 operates to reset the photodiode 34.2 to a known state.

A schematic plan view of the conventional image sensor is illustrated inFIG. 3. The conventional image sensor comprises a matrix of rows andcolumns of pixel elements indicated generally by reference numeral 52.Each of the pixel elements contains a photosensing structure andcorresponding support circuitry, such as the photodiode 34.2 and activepixel circuit 40, respectively, illustrated in FIG. 2.

There are many image sensor applications wherein a light source isrequired to illuminate a scene, or an object, so that the image sensorcan capture one or more images. Examples of such applications includebut are not limited to video surveillance, cell phones, digital camerasand digital video systems. During low ambient light level conditions thelight source is necessary for an image to be captured at all.

An example of a conventional infrared video surveillance camera is givenby U.S. Pat. No. 6,642,955 by Brent Midgley et al. Midgley describes aCCD type image sensor in a camera system that switches electronicallybetween infrared radiation sensing and visible light sensing dependingon ambient conditions. Furthermore, the camera in Midgley makes use ofeither incandescent or LED type illuminators. These illuminators arelocated external to the camera system, but may be in a camera systemenclosure along with the CCD image sensor.

An example of a CMOS sensor used in cell phone is given by U.S. Pat. No.6,730,900 by Hsish et al. in which is described a novel CMOS basedactive sensor array that, along with focusing optics, is preferablyincorporated into a cellular phone camera for producing electronicimages.

A disadvantage of the prior art is the lack of integration of a lightsource for image illumination with the image sensor. This has resultedin excessively large image sensor products for the applications listedabove. In the case of the video surveillance camera, the illuminator iseither in a separate enclosure altogether, or is mounted inside thecamera system enclosure thereby increasing the size.

Another disadvantage of the lack of integration is the inability to takeadvantage of an illumination apparatus. In a cell phone, for example,where space is a constrained, it is often not feasible to include theillumination apparatus. In this situation, a cell phone camera can onlybe used in conditions where ambient light is sufficient for itsoperation.

Furthermore, another disadvantage of the prior art is that by lack ofintegration the power consumption of the above mentioned products andapplications is excessively large.

BRIEF SUMMARY OF INVENTION

In an aspect of the present invention there is provided a light emittingand image sensing device for a scene. The light emitting and imagesensing device is formed in a semiconductor substrate and comprises aphotoemitter means for illuminating the scene with light, and aphotosensor means for sensing an image of the scene. The photosensormeans is responsive to incident light from the scene.

In another aspect of the invention there is provided a light emittingand image sensing device that includes a photosensor means. Thephotosensor means comprises a matrix of rows and columns of photosensorstructures responsive to incident light upon the light emitting andimage sensing device. For each row in the matrix there is row selectcircuitry connected to each of the photosensor structures in the row forselectively designating for outputting output signals representative ofthe light sensed by the photosensor structure. For each column in thematrix there is column select circuitry connected to each of thephotosensor structures in the column for selectively designating foroutputting output signals representative of the light sensed by thephotosensor structures.

In another aspect of the invention there is provided a light emittingand image sensing device having a photoemitter means. The photoemittermeans includes an array of photoemitter structures operable to emitlight from the device and a photoemitter control means for controllingan emission of the light from the array of photoemitter structures.

In another aspect of the invention there is provided a light emittingand image sensing device having a photosensor means. The photosensormeans comprises a plurality of select lines, a plurality of signallines, and a plurality of pixel elements. The pixel elements include aphotosensor structure, and a switching means coupled between thephotosensor structure and one of the plurality of signal lines. Theswitching means is responsive to select signals on one or more of theplurality of select lines for conveying a photosensor signal between thephotosensor structure and the one of the plurality of signal lines.

In another aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The light emitting andimage sensing device includes a photosensor means for sensing an imageof the scene and a photoemitter means for illuminating the scene withlight. The photosensor means is formed in a first semiconductorsubstrate and is responsive to incident light from the scene. Thephotoemitter means is formed in a second semiconductor substrate. Thesecond semiconductor substrate is attached to the first semiconductorsubstrate.

In another aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The light emitting andimage sensing device includes a photosensor means for sensing an imageof the scene and a photoemitter means for illuminating the scene withlight. The photosensor means is formed in a first semiconductorsubstrate and is responsive to incident light from the scene. Thephotoemitter means is formed in a second semiconductor substrate. Thesecond semiconductor substrate is attached to the first semiconductorsubstrate. The light emitting and image sensing device further includesa photoemitter control circuit operable to control an emission of thelight from the photoemitter means. The photoemitter control circuit isformed in the first semiconductor substrate.

In another aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The light emitting andimage sensing device includes a photosensor means for sensing an imageof the scene and a photoemitter means for illuminating the scene withlight. The photosensor means is formed in a first semiconductorsubstrate and is responsive to incident light from the scene. Thephotoemitter means is formed in a second semiconductor substrate. Thesecond semiconductor substrate is attached to the first semiconductorsubstrate. The photosensor means includes a matrix of rows and columnsof photosensor structures responsive to incident light upon the device.For each row in the matrix there is row select circuitry connected toeach of the photosensor structures in the row for selectivelydesignating for outputting output signals representative of the lightsensed by said photosensor structure. For each column in the matrixthere is column select circuitry connected to each of the photosensorstructures in said column for selectively designating for outputtingoutput signals representative of the light sensed by said photosensorstructures.

In another aspect of the invention there is provided a light emittingand image sensing device that is formed in a semiconductor substrate.The light emitting and image sensing device comprises a photoemitteroperable to emit electromagnetic radiation from the device, and aphotosensor responsive to electromagnetic radiation incident upon thedevice.

In another aspect of the invention there is provided a lens housing foran image sensor type camera, the camera for generating an image of ascene. The lens housing comprises a first light channel for guiding anemission of light from the image sensor to illuminate the scene, and asecond light channel for guiding light from the scene towards the imagesensor.

In another aspect of the invention there is provided a housing for alight emitting and image sensing device. The housing comprises a firstlight channel for emitted light from the light emitting and imagesensing device to illuminate a scene, and a second light channel forincident light from the scene towards the light emitting and imagesensing device.

In another aspect of the invention there is provided a housing for alight emitting and image sensing device. The housing comprises a firstlight channel for emitted light from the light emitting and imagesensing device to illuminate a scene, and a second light channel forincident light from the scene towards the light emitting and imagesensing device. The second light channel has an outer surface. The firstand second light channels have a common axis. The first light channelbeing formed around the outer surface of the second light channel.

In another aspect of the invention there is provided, in combination, alight emitting and image sensing device and a housing. The housing has afirst end where the light emitting and image sensing device is disposed.

In another aspect of the invention there is provided a method ofilluminating a scene and sensing an image. The method comprises thesteps of emitting light from a light emitting and image sensing device,channelling the emitted light along a first channel, dispersing thelight with a first lens towards the scene, focusing incident light fromthe scene with a second lens, channelling the focused light along asecond channel towards the light emitting and image sensing device, andsensing the image of the scene with the focused light upon the lightemitting and image sensing device.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be more readily understood from the followingdescription of preferred embodiments thereof given, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view in cross-section of a conventional CMOS imagesensor.

FIG. 2 is a schematic view of a conventional active pixel element.

FIG. 3 is a schematic plan view of a conventional image sensor.

FIGS. 4 a–h are schematic plan views of embodiments of light emittingand image sensing devices.

FIG. 5 is a schematic view in cross-section of an embodiment of thelight emitting and image sensing device in a silicon substrate.

FIG. 6 is a schematic view in cross-section of another embodiment of thelight emitting and image sensing device in a silicon substrate.

FIG. 7 is a broken-away schematic view in cross-section of an embodimentof the light emitting and image sensing device wherein a photoemitter isin a first semiconductor substrate and a pixel element is in a secondsemiconductor substrate.

FIG. 8 is a schematic view in cross-section of another embodiment of thelight emitting and image sensing device wherein a photoemitter is in afirst semiconductor substrate and a pixel element is in a secondsemiconductor substrate.

FIG. 9 is a partial schematic view of a matrix of active pixel elementsof the light emitting and image sensing device of FIG. 5.

FIG. 10 is a schematic view of an active pixel element of the lightemitting and image sensing device of FIG. 5.

FIG. 11 a–b are schematic views of embodiments of light emitting andimage sensing devices wherein an array of photoemitters is connected toa photoemitter control means.

FIG. 12 is a schematic view in perspective of the light emitting andimage sensing devices of the embodiments of FIGS. 4 a–c.

FIG. 13 is a schematic view in perspective of the light emitting andimage sensing devices of the embodiments of FIGS. 4 e–g.

FIG. 14 is a partial schematic view in perspective of the light emittingand image sensing device of the embodiment of FIG. 4 h.

FIG. 15 is a schematic view in perspective of an embodiment of a housingfor the light emitting and image sensing device of FIG. 4 h.

FIG. 16 is a cross-sectional schematic view of an embodiment of theinvention including the housing of FIG. 15 taken along line 16–16′, thelight emitting and image sensing device of FIG. 4 h, and a substrate.

FIG. 17 is a schematic view in perspective of an embodiment of a housinghaving adjacent light channels.

FIG. 18 is a cross-sectional schematic view of an embodiment of theinvention including the housing of FIG. 17 taken along line 18–18′,either one of the light emitting and image sensing devices of FIGS. 4e–g, and a substrate.

FIG. 19 is a schematic view in perspective of an embodiment of a housinghaving light channels with a common axis.

FIG. 20 is a cross-sectional schematic view of an embodiment of theinvention including the housing of FIG. 19 taken along line 20–20′,either one of the light emitting and image sensing devices of FIGS. 4a–d, and a substrate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 4 a, a light emitting and image sensing device,indicated generally by reference numeral 60, is formed in asemiconductor and has a light emitting region 62 and an image sensingregion 64 separated by an optical barrier 88. The light emitting region62 has a photoemitter 68. The photoemitter 68 operates to emit light,from a surface 66, to illuminate a scene, or an object. The emittedlight is in a range of wavelengths, which can be in an infrared band, avisible light band or an ultraviolet band of the electromagneticspectrum. Other bands of the electrical magnetic spectrum are, however,possible as well.

The image sensing region 64 has a plurality of pixel elements indicatedgenerally by reference numeral 70. The pixel elements 70 are responsiveto incident light from the scene, or the object. Each of the pixelelements 70 provides a photosensor signal representative of the incidentlight in the area of the respective pixel element. The plurality ofpixel elements 70 can be arranged in a matrix having rows and columns.An image sensor resolution is determined by a first number of pixelelements in each row and by a second number of pixel elements in eachcolumn.

Two further embodiments of the invention similar to the embodiment shownin FIG. 4 a are illustrated in FIGS. 4 b and 4 c wherein like parts havelike reference numerals with an additional suffix. The embodimentillustrated in FIG. 4 b includes a plurality of photoemitters 68.bpositioned in a photoemitter region 62.b around an image sensing region64.b, the regions separated by an optical barrier 88.b. The embodimentillustrated in FIG. 4 c includes a plurality of photoemitters 68.chaving a photoemitter density comparable to a pixel element density.

Another embodiment of the invention is illustrated in FIG. 4 d whereinlike parts have like reference numerals with an additional suffix. Thelight emitting and image sensing device 60.d has a circular imagesensing region 64.d surrounded by a ring-shaped light emitting region62.d, the regions separated by optical barrier 88.d. The light emittingregion 62.d has a plurality of photoemitters 68.d. The image sensingregion 64.d has a plurality of pixel elements 70.d.

Three further embodiments of the invention are illustrated in FIGS. 4 e,4 f and 4 g wherein like parts have like reference numerals with anadditional suffix. The embodiment illustrated in FIG. 4 e includes alight emitting region 62.e adjacent an image sensing region 64.e, theregions separated by an optical barrier 88.e. The light emitting region62.e includes a photoemitter 68.e and the image sensing region 64.eincludes a plurality of pixel elements 70.e. The plurality of pixelelements 70.e can be arranged in a matrix having rows and columns. Theembodiments illustrated in FIGS. 4 f and 4 g are similar to that of FIG.4 e, both including a plurality of photoemitters 68.f and 68.grespectively. The plurality of photoemitters 68.g has a photoemitterdensity comparable to a pixel element density.

Another embodiment of the invention is illustrated in FIG. 4 h whereinlike parts have like reference numerals with an additional suffix. Inthis embodiment a plurality of photoemitters 68.h are arranged in analternating pattern with a plurality of pixel elements 70.h. Aphotoemitter density can be different than a pixel element density.

Another embodiment of the invention is illustrated in FIG. 5, whereinlike parts have like reference numerals with an additional suffix. Aphotoemitter indicated generally by reference numeral 68.5 is separatedfrom a pixel element indicated generally by reference numeral 70.5. Thephotoemitter 68.5 and the pixel element 70.5 are formed on and in afirst layer of silicon 74. The first layer of silicon is formed on topof a silicon oxide (SiO₂) layer 76, which is formed on top of a siliconsubstrate 78.

In this embodiment the photoemitter 68.5 is similar to a semiconductordevice for electro-optic applications described in European PatentEP1210752 by Coffa et al., which is incorporated by reference herein. AnN− region 80, an N region 82 and a P+ region 84 are formed in thesilicon layer 74, and together make a PN junction that under reversebias emits light 92. One skilled in the art will recognize that the PNjunction is similar to a base-collector junction of a bipolar transistorhaving a base electrode 83, a collector electrode 85 and an emitterelectrode 87. A rare earth ions doped region 86, in this case Erbium,enables the PN junction to emit light 92 having a wavelength around 1.54um. Using other rare earth ions allows light to be emitted havingdifferent wavelengths. For instance, as a non-limiting example, Terbiumand Ytterbium provide light having a wavelength around 540 nm and 980 nmrespectively.

A trench, indicated generally by reference numeral 88.5, serves toreduce lateral light transmission from the rare earth ions doped region86 towards the pixel element 70.5. The trench 88.5 has a wall 90 uponwhich there is a film of silicon oxide (SiO₂) 91. Light 92 travellingfrom the rare earth ions doped region 86 towards the pixel element 70.5through the semiconductor layer 74 must cross the wall 90 and travelthrough the film of silicon oxide (SiO₂) 91. The refractive index ofsilicon oxide (SiO₂) is less than the refractive index of silicon. Thiscauses light incident on the wall 90 having an angle of incidence, froma normal to the wall, greater than a critical angle to undergo totalinternal reflection. In other embodiments multiple trenches having filmsof silicon oxide (SiO₂) can be used to further reduce lateral lighttransmission. The trench 88.5 has the advantage of reducing phantomimages in and preventing blurring of pixel element 70.5 as caused by theabove mentioned lateral light transmission.

The light 92 emitted from the rare earth ions doped region 86 has randomdirections. The light 92 strikes a surface 104, defined by a boundarybetween the silicon layer 74 and a silicon oxide layer 106, at variousangles of incidence to a normal to the surface. Light 92 having theangle of incidence greater then the critical angle will be internallyreflected. It is advantageous, then, that the light 92 be substantiallynormal to the surface 104 in order for maximum light emission from thesurface. The goal is to maximize an external quantum efficiency, aproblem well known in the art. In another embodiment, a photoemitter canbe provided similar to a device presented in “Si-based Resonant CavityLight Emitting Devices” by Castagna et al in SPIE Vol 5366, which isincorporated by reference herein. This has the advantage that lightgenerated is substantially normal to surface 104. This has a furtheradvantage of reducing lateral light transmission through thesemiconductor layer 74 towards the pixel element 70.5.

The pixel element 70.5 of the present embodiment is commonly known inthe prior art, as disclosed by U.S. Pat. No. 5,965,875 by Merril, whichis incorporated by reference herein. and as such will not be describedin great detail here. The pixel element 70.5 includes a photosensorstructure 72. The photosensor structure 72 is based on a triple wellstructure forming a first PN junction 94, a second PN junction 96 and athird PN junction 98. Incident light 100 having different wavelengthspenetrates the photosensor structure 72 at varying depths depending onthe wavelength. Red light penetrates to around the depth of the first PNjunction 94 where it produces a red photo current. Green lightpenetrates to around the depth of the second PN junction 94 where itproduces a green photo current. Blue light penetrates to around thedepth of the third PN junction 94 where it produces a blue photocurrent. A photocurrent sensor indicated generally by reference numeral102 measures the red, green and blue photocurrents.

When the incident light 100 is in the near ultraviolet and near infraredbands of the electromagnetic spectrum, the photosensor structure 72 isstill capable of functioning well. A study performed by AlternativeVision Corporation indicates that the photosensor structure 72 performswell under such conditions. The results of the study were published in apaper titled “Infrared and ultraviolet imaging with a CMOS sensor havinglayered photodiodes” by Gilblom et al.

The pixel element 70.5 of this embodiment is advantageous since it takesless area of surface 104 to sense red, green and blue components oflight 100. This allows increased resolution for a given surface area.Nevertheless, other image sensor structures formed in silicon can beused for the present invention. This includes CMOS image sensorstructures, such as in FIG. 1, and CCD image sensor structures.

Referring now to FIG. 6, another embodiment of the invention isillustrated wherein like parts have like reference numerals with anadditional suffix. The photoemitter 68.6 is in this case formed using aPN junction diode, indicated generally by reference numeral 108, withun-annealed implant dislocations used to enhance light emission. Thestructure of the PN junction diode 108 is described in great detail inU.S. Pat. No. 6,710,376 by Worley, which is incorporated by referenceherein. The pixel element 70.6 is similar to the pixel element 70.5 inFIG. 5.

The PN junction 108 is comprised of an N+implant region 110, in a dopedP type region 112, and a P+implant 114 that is used to make a goodelectrical connection between the P-type region and metal terminals 116.A connection is made to the N+implant region 110 using the metalterminal 118.

Several light emitting devices are known in the prior art that use III–Vor II–VI semiconductors and compound semiconductors, for example LEDs,resonant cavity light emitting diodes (RCLED) and vertical cavitysurface emitting lasers (VCSEL). It would be advantageous to includethese types of devices with a silicon based image sensor.

Another embodiment of the invention is illustrated in FIG. 7 whereinlike parts have like reference numerals with an additional suffix. Afirst semiconductor substrate 120 is illustrated above a secondsemiconductor substrate 122. The first semiconductor substrate 120 isformed from III–V or II–VI compound semiconductor materials, whereas thesecond semiconductor substrate 122 is formed from silicon. Aphotoemitter 68.7 is formed in the first semiconductor substrate 120,and a pixel element 70.7 is formed in the second semiconductor substrate122. Any one of the photoemitters 68 and 68 b–h can a structure similarto photoemitter 68.7. The pixel element 70.7 is similar to the pixelelement 70.5 in FIG. 5.

In the present embodiment, the photoemitter 68.7 is similar to a lightemitting device disclosed in U.S. Pat. 5,493,577 by Choquette et al,which is incorporated by reference herein, wherein the light emittingdevice has a structure compatible for both RCLEDs and VCSELs. Thephotoemitter 68.7 comprises a first distributed Bragg reflector (DBR)124, a second DBR 126, an active region 128 and a control layer 130. Thefirst and second DBRs 124 and 126 and the active region 128 form aresonator, or what is commonly called a Fabry-Perot resonator. Asubstrate 132 attaches the first DBR 124 to a first electrode 134. Asecond electrode 136 is deposited on the second DBR 126. Choquettedescribes the operation of the photoemitter 68.7 for RCLED and VCSELembodiments in great detail.

Light 92.7 is emitted substantially along an axis and normal to asurface 40. Since the index of refraction of the second DBR 126 isgreater than that of air, the surrounding environment, this has theadvantage of minimizing the effects of internal reflection at thesurface 140. This increases an external quantum efficiency of thephotoemitter 68.7. Another advantage of the orientation of light 92.7 tosurface 140 is that light is substantially not emitted towards thephotosensor structure 72.7. This prevents the formation of phantomimages in and/or blurring of the pixel element 70.7. In this embodimentthe light 92.7 has a wavelength of 980 nm which is in the near infraredregion.

The first semiconductor substrate 120 is attached to the secondsemiconductor substrate 122. The first electrode 134 is operativelyconnected to photoemitter control circuitry 138, which can enable,disable and control the intensity of light emission of the photoemitter68.7. Attaching different types of semiconductor substrates together,for instance GaAs and Si, and providing many electrical connectionsbetween them is well known in the art. The company Xanoptix Inc.provides such hybrid integrated circuit technology.

In another embodiment, a light emitting and image sensing device using aIII–V compound semiconductor substrate and a silicon substrate isillustrated in FIG. 8, wherein like parts have like reference numeralswith an additional suffix. In this embodiment, the photoemitter 68.8,again, is formed in the first semiconductor substrate 120.8, and thepixel element 70.8 is formed in a second semiconductor substrate 122.8.The photoemitter 68.8 is similar in structure to a VCSEL disclosed inU.S. Pat. No. 6,590,017 by Nakayama et. al., which is incorporated byreference herein. The photoemitter 68.8 includes an n-type GaAssubstrate 150, an epitaxial n-type GaAs layer 152, an n-type DBR 154, anactive layer region 156, a p-type DBR 158, a first mode control layer160, a second mode control layer 162 and an electrode 164.

The photoemitter 68.8 is similar in structure to a VCSEL disclosed inU.S. Pat. No. 6,590,917 by Nakayama et al. The photoemitter 68.8includes an n-type GaAs substrate 150, an epitaxial n-type GaAs layer152, an n-type DBR 154, an active layer region 156, a p-type DBR 158, afirst mode control layer 160, a second mode control layer 162 and anelectrode 164.

Light 92.8, again, is emitted substantially normal to a surface 140.8having the advantage of increasing an external quantum efficiency andminimizing light emitted towards the photosensor structure 72.8. Awavelength of light emitted depends upon what material is used to formthe active layer region 156. If AlGaAs forms the active layer region 156the wavelength is around 780 nm. If the active layer region 156 materialis GaAs or InGaAs the wavelength is in the near infrared band. If theactive layer region 156 material is InGaP or AlGaInP the wavelength isin the red color visible light band. If the active layer region 156material is GaN or ZnSe the wavelength is in the blue color visiblelight band and ultraviolet band. If the active layer region 156 materialis InGaAsP the wavelength is around 1300 nm to 1500 nm.

Referring back to FIGS. 4 a–h, the light emitting and image sensingdevices 60 and 60 b–h include the plurality of pixel elements 70 and 70b–h respectively. Each one of the pixel elements 70 and 70 b–h can bethe pixel element 70.5 illustrated FIG. 5. In another embodiment, thepixel element 70.5 illustrated in FIGS. 5. and similarly the pixelelements 70.6. 70.7 and 70.8 illustrated in FIGS. 6, 7, and 8respectively, can be arranged in a matrix configuration as illustratedin FIG. 9, wherein like parts have like reference numerals with anadditional suffix. Four such pixel elements 70.9 are illustrated in FIG.9 in a matrix having two rows and two columns (2×2), however, there maybe any number of rows and columns. Each pixel element 70.9 comprises aphotosensor structure and an active pixel circuit indicated generally byreference numeral 72.9 and 170 respectively. The pixel element 70.9 isfurther illustrated in FIG. 10, wherein the active pixel circuit 170 ispresented in greater detail. The operation of the pixel elements 70.9 isdescribed in great detail in Merril. The pixel element 70.9 includes aselect line Col and signal lines ROW R. ROW G and ROW B. The activepixel circuit 170 in cooperation with the select line Col selectivelycouples the photosensor structure 72.9 to the signal lines ROW R. ROW Gand ROW B.

Again, referring back to FIGS. 4 b–d and 4 f–h, the light emitting andimage sensing devices 60 b–d and 60 f–h include a plurality ofphotoemitters 68 b–d and 68 f–h respectively. In another embodiment, aplurality of photoemitters 68.11 in a light emitting and image sensingdevice is controlled by a photoemitter controller 138.11 as illustratedin FIGS. 11 a–b, wherein like parts have like reference numerals with anadditional suffix. The photoemitter control means controller 138.11enables the photoemitters 68.11 to emit light, disables the emission oflight and controls the intensity of emitted light. The photoemittercontroller 138.11 can be an adjustable current source, for example,which is well known in the art. The light emitting and image sensingdevice includes the photoemitter controller 138.11. In otherembodiments, the photoemitter controller 138.11 can be external of alight emitting and image sensing device. In this case, the photoemitters68.11 are connected to the photoemitter controller 138.11 by anelectrical connector, for example a connecting pin, or pad.

Referring back to FIG. 5, and similarly with FIGS. 6, 7 and 8, thetrench 88.5 operates to reduce light transmission from the photoemitter68.5 towards the pixel element 70.5. In another embodiment of theinvention illustrated in FIG. 12, wherein like parts have like referencenumerals with an additional suffix, a trench 88.12 separates two regionsin a semiconductor layer 74.12, for instance a silicon layer. The trench88.12 extends from a surface 172 to a boundary surface 174 between thesemiconductor layer 74.12 and a layer 78.12, for instance a siliconoxide (SiO₂) layer.

A light emitting region 62.12 and an image sensing region 64.12correspond to the corresponding regions in the light emitting and imagesensing devices 60, 60.b and 60.c of FIGS. 4 a–c respectively. The lightemitting region 62.12 includes at least one photoemitter 68.12, whichcan be similar in structure to either one of the photoemitters 68.5,68.6, 68.7 and 68.8 of FIGS. 5, 6, 7 and 8 respectively, although otherstructures could also be used. The photoemitter 68.12 can be formed inlayer 74.12 or above layer 74.12 in another semiconductor substrate,depending on the nature of the photoemitter. The image sensing region64.12 includes a plurality of pixel elements indicated generally byreference numeral 70.12, which can be similar in structure to pixelelement 70.5 of FIG. 5, although other pixel elements structures can beused.

The trench 88.12 serves to substantially reduce light transmission fromthe light emitting region 62.12 through the semiconductor layer 74.12towards the image sensing region 64.12. When the semiconductor layer74.12 is silicon (or doped silicon) the trench 88.12 can have a wall,next to the light emitting region 62.12, which has a film of siliconoxide (SiO₂) thereon.

In another embodiment of the invention illustrated in FIG. 13, whereinlike parts have like reference numerals with an additional suffix, atrench 88.13 in a semiconductor substrate 74.13 separates a lightemitting region 62.13 and an image sensing region 64.13.

The light emitting region 62.13 and the image sensing region 64.13correspond to the corresponding regions in the light emitting and imagesensing devices 60 e–g of FIGS. 4 e–g respectively. The light emittingregion 62.13 includes at least one photoemitter 68.13, which can besimilar in structure to either one of the photoemitters 68.5, 68.6, 68.7and 68.8 of FIGS. 5, 6, 7 and 8 respectively, although other structurescould also be used. The photoemitter 68.13 can be formed in layer 74.13or above layer 74.13 in another semiconductor substrate, depending onthe nature of the photoemitter. The image sensing region 64.13 includesa plurality of pixel elements indicated generally by reference numeral70.13, which can be similar in structure to pixel element 70.5 of FIG.5, although other pixel elements structures can be used.

Again, the trench 88.13 serves to substantially reduce lighttransmission from the light emitting region 62.13 through thesemiconductor layer 74.13 towards the image sensing region 64.13.

FIG. 14 illustrates another embodiment of the invention, wherein likeparts have like reference numerals with an additional suffix. Aplurality of trenches 88.14 in a semiconductor substrate 74.14 separatea plurality of light emitting regions 62.14 from an image sensing region64.14. This embodiment corresponds to the light emitting and imagesensing device 60.h of FIG. 4 h.

Each of the plurality of light emitting regions 62.14 includes at leastone photoemitter 68.14, which can be similar in structure to either oneof the photoemitters 68.5, 68.6, 68.7 and 68.8 of FIGS. 5, 6, 7 and 8respectively, although other structures could also be used. Thephotoemitter 68.14 can be formed in layer 74.14 or above layer 74.14 inanother semiconductor substrate, depending on the nature of thephotoemitter. The image sensing region 64.14 includes a plurality ofpixel elements indicated generally by reference numeral 70.14, which canbe similar in structure to pixel element 70.5 of FIG. 5, although otherpixel elements structures can be used.

Another embodiment of the invention is illustrated in FIGS. 15 and 16,wherein like parts have like reference numerals with an additionalsuffix. Referring to FIG. 16 first, a light emitting and image sensingdevice 60.16 is mounted on a substrate 182, for instance a printedcircuit board (PCB), and a single light channel housing 180 is mountedto the substrate overtop the light emitting and image sensing device.The light emitting and image sensing device 60.16 in this embodiment canbe the light emitting and image sensing device 60.h illustrated in FIG.4 h.

Referring to FIGS. 15 and 16, the single channel housing 180 has a firstend 184 and a second end 186 and a light channel 185. A lens 188 isattached at the first end 184. The first and second ends 184 and 186 canhave different shapes, for instance circular, square or rectangular. Thelight channel 185 has an inner surface 187. The inner surface 187 can beshaped such that at the first end 184 it is one shape, for instanceannular, and at the second end 186 it is a second shape, for instancesquare, with a smooth transformation of the inner surface between theends 184 and 186.

Another embodiment of the invention is illustrated in FIGS. 17 and 18,wherein like parts have like reference numerals with an additionalsuffix. Referring to FIG. 18 first, a light emitting and image sensingdevice 60.18 is mounted on a substrate 182.18, and an adjacent lightchannel housing 180.18 is mounted to the substrate overtop the lightemitting and image sensing device. The light emitting and image sensingdevice 60.18 in this embodiment can be either one of the light emittingand image sensing devices 60.e, 60.f and 60.g illustrated in FIGS. 4 e,4 f and 4 g respectively.

Referring to FIGS. 17 and 18, the adjacent light channel housing 180.18has a first light channel 190 adjacent a second light channel 192. Thefirst light channel 190 has opposite ends 194 and has a lens 198attached at one end thereof. The lens 198 can be biconcave as well asother types of diverging lenses. Light from a light emitting region62.18 of the light emitting and image sensing device 60.18 travelsthrough lens 198 towards a scene, or an object. The lens 200 can bebiconvex as well as other types of converging lenses. The opposite ends194 can have different shapes, for instance circular, rectangular orsquare. The second light channel has opposite ends 196 and has a lens200 attached at one end thereof. Light from the scene or the objecttravels through lens 200 towards an image sensing region 64.18 of thelight emitting and image sensing device 60.18. The opposite ends 196 canhave different shapes, for instance circular, rectangular or square.

Another embodiment of the invention is illustrated in FIGS. 19 and 20,wherein like parts have like reference numerals with an additionalsuffix. Referring to FIG. 20 first, a light emitting and image sensingdevice 60.20 is mounted on a substrate 182.20, and a dual light channelhousing 180.20 is mounted to the substrate overtop the light emittingand image sensing device. The light emitting and image sensing device60.20 in this embodiment can be either of the light emitting and imagesensing devices 60, 60.b and 60.c of FIGS. 4 a, 4 b and 4 crespectively.

Referring to FIGS. 19 and 20, the dual light channel housing 180.20 hasa first light channel 190.20, having an axis 191, and a second lightchannel 192.20 having the same axis 191. The first light channel hasopposite ends 194.20 and has a lens 198.20 attached at one end thereof.The lens 198.20 can be biconcave as well as other types of diverginglenses. Light from a light emitting region 62.20 of the light emittingand image sensing device 60.20 travels through the lens 198.20 andtowards a scene, or an object. The opposite ends 194.20 can havedifferent shapes, for instance circular, rectangular or square. Thesecond light channel has opposite ends 196.20 and has a lens 200.20attached at one end thereof. The lens 200.20 can be biconvex as well asother types of converging lenses. Light from the scene, or the object,travels through the lens 200.20 towards an image sensing region 64.20 ofthe light emitting and image sensing device 60.20. The opposite ends196.20 can have different shapes, for instance circular, rectangular orsquare. Typically, the shapes of the opposite ends 194.20 of the firstlight channel 190.20 correspond to the shapes of the opposite ends196.20 of the second light channel 192.20.

The embodiments illustrated in FIGS. 15–20 have the advantage ofproviding a small form factor apparatus that has image sensing and lightemitting functionality together with focusing optics. This isparticularly advantageous for cellular phones, providing video callfunctionality, where space is inherently very limited. Using theapparatus of the above embodiments no extra space would be required forthe illuminator. This is also advantageous for video surveillanceapplications where the conventional approach to provide an illuminatorwith an image sensor is to provide an annular ring of light emittingdiodes around the image sensor lens housing. With the above apparatusthis no longer needs to be done. Now, for example, the videosurveillance camera can easily be incorporated into a wall withoutrequiring additional holes in the wall for LED illuminators. Otherapplications can take similar advantage of the above embodiments.

As will be apparent to those skilled in the art, modifications can bemade to the above-described invention within the scope of the appendedclaims.

1. A light emitting and image sensing device for a scene, the deviceformed in a semiconductor substrate, the device comprising: aphotoemitter means for illuminating the scene with light; a photosensormeans for sensing an image of the scene, the photosensor meanscomprising: a plurality of select lines; a plurality of signal lines;and a plurality of pixel elements, each pixel element including: aphotosensor structure; and switching means for conveying a photosensorsignal between the photosensor structure and one of the plurality ofsignal lines, the switching means being coupled between the photosensorstructure and the one of the plurality of signal lines, the switchingmeans being responsive to select signals on one or more of the pluralityof select lines for conveying the photosensor signal; the photosensormeans being responsive to incident light from the scene.
 2. A lightemitting and image sensing device for a scene comprising: a photosensormeans for sensing an image of the scene, the photosensor means being ona first semiconductor substrate and being responsive to incident lightfrom the scene; a photoemitter means for illuminating the scene withlight, the photoemitter means being on a second semiconductor substrate;and a photoemitter control means for controlling an emission of lightfrom the photoemitter means, the photoemitter control means being on thefirst semiconductor substrate; wherein the second semiconductorsubstrate is connected with the first semiconductor substrate.
 3. Alight emitting and image sensing device for a scene, the device formedon a semiconductor substrate, the device comprising: a photoemittermeans for illuminating the scene with light, said photoemitter meansincluding a resonator; and a photosensor means for sensing an image ofthe scene including: a plurality of select lines; a plurality of signallines; and a plurality of pixel elements, each pixel element including:a photosensor structure; and switching means for conveying a photosensorsignal between the photosensor structure and one of the plurality ofsignal lines, the switching means being coupled between the photosensorstructure and the one of the plurality of signal lines, the switchingmeans being responsive to select signals on one or more of the pluralityof select lines for conveying the photosensor signals; wherein saidphotosensor means is responsive to incident light from the scene.
 4. Alight emitting and image sensing device for a scene comprising: aphotosensor means for sensing an image of the scene being on a firstsemiconductor substrate and being responsive to incident light from thescene, the photosensor means including: a plurality of select lines; aplurality of signal lines; and a plurality of pixel elements, each pixelelement including: a photosensor structure; and switching means forconveying a photosensor signal between the photosensor structure and oneof the plurality of signal lines, the switching means being coupledbetween the photosensor structure and the one of the plurality of signallines, the switching means being responsive to select signals on one ormore of the plurality of select lines for conveying the photosensorsignal; and a photoemitter means for illuminating the scene with light,the photoemitter means being on a second semiconductor substrate, saidphotoemitter means including a resonator, the second semiconductorsubstrate being connected with the first semiconductor substrate.
 5. Alight emitting and image sensing device for a scene comprising: aphotosensor means for sensing an image of the scene, the photosensormeans being on a first semiconductor substrate and being responsive toincident light from the scene; a photoemitter means for illuminating thescene with light, the photoemitter means being on a second semiconductorsubstrate, said photoemitter means including a resonator, the secondsemiconductor substrate being connected with the first semiconductorsubstrate; and a photoemitter control means for controlling an emissionof light from the photoemitter means, the photoemitter control meansbeing on the first semiconductor substrate.
 6. The device as claimed inclaim 1, wherein the semiconductor substrate is a silicon substrate, thephotoemitter means and the photosensor means being formed in the siliconsubstrate.
 7. The device as claimed in claim 1, wherein a wavelength ofthe light is within the range 100 micrometers to 10 nanometers.
 8. Thedevice as claimed in claim 1, wherein the device further includes aphotoemitter control circuit operable to control an emission of thelight from the photoemitter means, the control circuit being formed inthe semiconductor substrate.
 9. The device as claimed in claim 1,wherein the device further includes an electrical connector forconnecting an external photoemitter control circuit operable to controlan emission of the light from the photoemitter means.
 10. The device asclaimed in claim 1, wherein the device further includes an opticalbarrier means for substantially optically separating the photoemittermeans from the photosensor means, the optical barrier means being formedin the semiconductor substrate.
 11. The device as claimed in claim 10,wherein the optical barrier means includes a trench in the semiconductorsubstrate having a pair of walls on opposite sides thereof, at least oneof said walls having a coating of silicon oxide (SiO₂).
 12. The deviceas claimed in claim 1, wherein the photoemitter means includes a lightemitting diode.
 13. The device as claimed in claim 6, wherein thephotoemitter means includes a PN junction implanted with a rare earthion.
 14. The device as claimed in claim 1, wherein the photoemittermeans includes a resonant cavity light emitting diode.
 15. The device asclaimed in claim 1, wherein the photoemitter means includes a verticalcavity surface emitting laser.
 16. The device as claimed in claim 6,wherein the photoemitter means includes a MOS capacitor having a gatedielectric, the MOS capacitor being formed on the silicon substrate, thegate dielectric being implanted with a rare earth ion.
 17. The device asclaimed in claim 1, wherein the photoemitter means includes an array ofphotoemitter structures operable to emit light from the device.
 18. Thedevice as claimed in claim 17, wherein the photoemitter means furtherincludes a photoemitter control means for controlling an emission of thelight from the array of photoemitter structures.
 19. The device asclaimed in claim 2, wherein the first semiconductor substrate is asilicon substrate.
 20. The device as claimed in claim 2, wherein thephotoemitter control means includes a connecting means for an externalphotoemitter control circuit operable to control an emission of thelight from the photoemitter means.
 21. The device as claimed in claim 2,wherein the photoemitter means includes a light emitting diode.
 22. Thedevice as claimed in claim 2, wherein the photoemitter means includes aresonant cavity light emitting diode.
 23. The device as claimed in claim2, wherein the photoemitter means includes a vertical cavity surfaceemitting laser.
 24. The device as claimed in claim 2, wherein thephotosensor means comprises: a matrix of rows and columns of photosensorstructures responsive to incident light upon the device; for each row insaid matrix, row select circuitry connected to each of the photosensorstructures in said row for selectively designating for outputting outputsignals representative of the light sensed by said photosensorstructure; and for each column in said matrix, column select circuitryconnected to each of the photosensor structures in said column forselectively designating for outputting output signals representative ofthe light sensed by said photosensor structures.
 25. The device asclaimed in claim 2, wherein the photoemitter means includes an array ofphotoemitter structures operable to emit light from the device.
 26. Thedevice as claimed in claim 2, wherein the photosensor means comprises: aplurality of select lines; a plurality of signal lines; and a pluralityof pixel elements, each pixel element including: a photosensorstructure; and switching means for conveying a photosensor signalbetween the photosensor structure and one of the plurality of signallines, the switching means being coupled between the photosensorstructure and the one of the plurality of signal lines, the switchingmeans being responsive to select signals on one or more of the pluralityof select lines for conveying the photosensor signal.
 27. The device asclaimed in claim 3, wherein the photoemitter means includes a resonantcavity light emitting diode.
 28. The device as claimed in claim 3,wherein the photoemitter means includes a vertical cavity surfaceemitting laser.
 29. The device as claimed in claim 3, wherein saidresonator includes a first distributed Bragg reflector, a seconddistributed Bragg reflector and an active region disposed between thefirst and second distributed Bragg reflectors.
 30. The device as claimedin claim 3, wherein the device further includes a photoemitter controlmeans for controlling an emission of the light from the photoemittermeans, the photoemitter control means being formed in the semiconductorsubstrate.
 31. The device as claimed in claim 5, wherein said resonatorincludes a first distributed Bragg reflector, a second distributed Braggreflector and an active region disposed between the first and seconddistributed Bragg reflectors.
 32. The device as claimed in claim 5,wherein the photoemitter means includes a resonant cavity light emittingdiode.
 33. The device as claimed in claim 5, wherein the photoemittermeans includes a vertical cavity surface emitting laser.
 34. The deviceas claimed in claim 5, wherein the photosensor means comprises: a matrixof rows and columns of photosensor structures responsive to incidentlight upon the device; for each row in said matrix, row select circuitryconnected to each of the photosensor structures in said row forselectively designating for outputting output signals representative ofthe light sensed by said photosensor structure; and for each column insaid matrix, column select circuitry connected to each of thephotosensor structures in said column for selectively designating foroutputting output signals representative of the light sensed by saidphotosensor structures.
 35. The device as claimed in claim 4, whereinsaid resonator includes a first distributed Bragg reflector, a seconddistributed Bragg reflector and an active region disposed between thefirst and second distributed Bragg reflectors.
 36. The device as claimedin claim 4, wherein the photoemitter means includes a resonant cavitylight emitting diode.
 37. The device as claimed in claim 4, wherein thephotoemitter means includes a vertical cavity surface emitting laser.